| Message ID | 4f6d4342-8476-882e-e7a8-b3f0ebd20d95@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 06/23/2017 10:43 AM, Jason Wang wrote: > > > On 2017年06月23日 02:53, Michael S. Tsirkin wrote: >> On Thu, Jun 22, 2017 at 08:15:58AM +0200, jean-philippe menil wrote: >>> 2017-06-06 1:52 GMT+02:00 Michael S. Tsirkin <mst@redhat.com>: >>> >>> On Mon, Jun 05, 2017 at 05:08:25AM +0300, Michael S. Tsirkin wrote: >>> > On Mon, Jun 05, 2017 at 12:48:53AM +0200, Jean-Philippe Menil >>> wrote: >>> > > Hi, >>> > > >>> > > while playing with xdp and ebpf, i'm hitting the following: >>> > > >>> > > [ 309.993136] >>> > > >>> ================================================================== >>> > > [ 309.994735] BUG: KASAN: use-after-free in >>> > > free_old_xmit_skbs.isra.29+0x2b7/0x2e0 [virtio_net] >>> > > [ 309.998396] Read of size 8 at addr ffff88006aa64220 by >>> task sshd/323 >>> > > [ 310.000650] >>> > > [ 310.002305] CPU: 1 PID: 323 Comm: sshd Not tainted >>> 4.12.0-rc3+ #2 >>> > > [ 310.004018] Hardware name: QEMU Standard PC (i440FX + >>> PIIX, 1996), >>> BIOS >>> > > 1.10.2-20170228_101828-anatol 04/01/2014 >> ... >> >>> > >>> > Since commit 680557cf79f82623e2c4fd42733077d60a843513 >>> > virtio_net: rework mergeable buffer handling >>> > >>> > we no longer must do the resets, we now have enough space >>> > to store a bit saying whether a buffer is xdp one or not. >>> > >>> > And that's probably a cleaner way to fix these issues than >>> > try to find and fix the race condition. >>> > >>> > John? >>> > >>> > -- >>> > MST >>> >>> >>> I think I see the source of the race. virtio net calls >>> netif_device_detach and assumes no packets will be sent after >>> this point. However, all it does is stop all queues so >>> no new packets will be transmitted. >>> >>> Try locking with HARD_TX_LOCK? >>> >>> -- >>> MST >>> >>> >>> Hi Michael, >>> >>> from what i see, the race appear when we hit virtnet_reset in >>> virtnet_xdp_set. >>> virtnet_reset >>> _remove_vq_common >>> virtnet_del_vqs >>> virtnet_free_queues >>> kfree(vi->sq) >>> when the xdp program (with two instances of the program to trigger it >>> faster) >>> is added or removed. >>> >>> It's easily repeatable, with 2 cpus and 4 queues on the qemu command >>> line, >>> running the xdp_ttl tool from Jesper. >>> >>> For now, i'm able to continue my qualification, testing if xdp_qp is >>> not null, >>> but do not seem to be a sustainable trick. >>> if (xdp_qp && vi->xdp_queues_pairs != xdp_qp) >>> >>> Maybe it will be more clear to you with theses informations. >>> >>> Best regards. >>> >>> Jean-Philippe >> >> I'm pretty clear about the issue here, I was trying to figure out a fix. >> Jason, any thoughts? >> >> > > Hi Jean: > > Does the following fix this issue? (I can't reproduce it locally through > xdp_ttl) > > Thanks > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 1f8c15c..3e65c3f 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1801,7 +1801,9 @@ static void virtnet_freeze_down(struct > virtio_device *vdev) > /* Make sure no work handler is accessing the device */ > flush_work(&vi->config_work); > > + netif_tx_lock_bh(vi->dev); > netif_device_detach(vi->dev); > + netif_tx_unlock_bh(vi->dev); > cancel_delayed_work_sync(&vi->refill); > Hi Jason, unfortunately, same crash on same place, the lock did not help. [ 574.522886] ================================================================== [ 574.527393] BUG: KASAN: use-after-free in free_old_xmit_skbs.isra.28+0x29b/0x2b0 [virtio_net] [ 574.531934] Read of size 8 at addr ffff88005d220020 by task iperf/2252 [ 574.536296] [ 574.539729] CPU: 1 PID: 2252 Comm: iperf Not tainted 4.12.0-rc5+ #5 [ 574.543916] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 [ 574.552046] Call Trace: [ 574.555648] dump_stack+0xb3/0x10b [ 574.559471] ? free_old_xmit_skbs.isra.28+0x29b/0x2b0 [virtio_net] [ 574.563578] print_address_description+0x6a/0x280 [ 574.567253] ? free_old_xmit_skbs.isra.28+0x29b/0x2b0 [virtio_net] [ 574.571223] kasan_report+0x22b/0x340 [ 574.574698] __asan_report_load8_noabort+0x14/0x20 [ 574.578490] free_old_xmit_skbs.isra.28+0x29b/0x2b0 [virtio_net] [ 574.582586] ? dev_queue_xmit_nit+0x5fb/0x850 [ 574.586348] ? virtnet_del_vqs+0xf0/0xf0 [virtio_net] [ 574.590153] ? __skb_clone+0x24a/0x7d0 [ 574.593835] start_xmit+0x15a/0x1620 [virtio_net] [ 574.597939] dev_hard_start_xmit+0x17f/0x7e0 [ 574.601832] sch_direct_xmit+0x2a8/0x5d0 [ 574.605665] ? dev_deactivate_queue.constprop.31+0x150/0x150 [ 574.609827] __dev_queue_xmit+0x1124/0x18b0 [ 574.613595] ? selinux_ip_postroute+0x4b2/0xa90 [ 574.617928] ? netdev_pick_tx+0x2d0/0x2d0 [ 574.621852] ? mark_held_locks+0xc8/0x120 [ 574.625673] ? ip_finish_output+0x626/0x9b0 [ 574.631679] ? ip_finish_output2+0xb44/0x1160 [ 574.637642] dev_queue_xmit+0x17/0x20 [ 574.641693] ip_finish_output2+0xcd1/0x1160 [ 574.645621] ? do_add_counters+0x480/0x480 [ 574.649554] ? do_add_counters+0x403/0x480 [ 574.653209] ? ip_copy_metadata+0x630/0x630 [ 574.657066] ip_finish_output+0x626/0x9b0 [ 574.660482] ? ip_finish_output+0x626/0x9b0 [ 574.663905] ip_output+0x1e2/0x580 [ 574.667235] ? ip_mc_output+0xe80/0xe80 [ 574.670574] ? ip_fragment.constprop.57+0x200/0x200 [ 574.673949] ip_local_out+0x95/0x160 [ 574.677249] ? __sk_dst_check+0xa7/0x260 [ 574.680446] ip_queue_xmit+0x889/0x17f0 [ 574.683575] ? __tcp_v4_send_check+0x1b8/0x350 [ 574.686801] tcp_transmit_skb+0x194a/0x2db0 [ 574.689832] ? __tcp_select_window+0x500/0x500 [ 574.693310] ? sched_clock_cpu+0x1b/0x190 [ 574.696371] ? tcp_grow_window.isra.24+0x2a8/0x4b0 [ 574.699509] tcp_send_ack+0x46f/0x710 [ 574.702395] __tcp_ack_snd_check+0x233/0x380 [ 574.705365] tcp_rcv_established+0x14eb/0x2230 [ 574.708332] ? trace_hardirqs_on_caller+0x3f4/0x560 [ 574.711800] ? tcp_data_queue+0x3e70/0x3e70 [ 574.714761] ? sk_wait_data+0x2af/0x400 [ 574.719220] tcp_v4_do_rcv+0x56c/0x820 [ 574.724018] tcp_prequeue_process+0x18f/0x2c0 [ 574.729062] tcp_recvmsg+0xff6/0x26a0 [ 574.734615] ? tcp_tx_timestamp.part.27+0x290/0x290 [ 574.739519] ? _copy_from_user+0x84/0xe0 [ 574.744115] ? rw_copy_check_uvector+0x1f6/0x290 [ 574.748722] ? sock_has_perm+0x1e4/0x270 [ 574.751537] ? selinux_tun_dev_create+0xc0/0xc0 [ 574.754068] inet_recvmsg+0x117/0x530 [ 574.756823] ? memzero_page+0x130/0x130 [ 574.759503] ? inet_sk_rebuild_header+0x1880/0x1880 [ 574.762303] ? selinux_socket_recvmsg+0x36/0x40 [ 574.765114] ? security_socket_recvmsg+0x8f/0xc0 [ 574.768156] ? inet_sk_rebuild_header+0x1880/0x1880 [ 574.771181] sock_recvmsg+0xd7/0x110 [ 574.773972] ? __sock_recv_wifi_status+0x180/0x180 [ 574.777002] ___sys_recvmsg+0x24d/0x560 [ 574.779789] ? ___sys_sendmsg+0x920/0x920 [ 574.782734] ? __fget+0x200/0x380 [ 574.785657] ? lock_downgrade+0x650/0x650 [ 574.788584] ? __fget+0x229/0x380 [ 574.791362] ? __fget_light+0xa1/0x1f0 [ 574.794162] ? __fdget+0x18/0x20 [ 574.796832] __sys_recvmsg+0xce/0x170 [ 574.799572] ? __sys_recvmsg+0xce/0x170 [ 574.802695] ? SyS_sendmmsg+0x60/0x60 [ 574.805461] ? __schedule+0x7cb/0x1a70 [ 574.808211] ? retint_kernel+0x10/0x10 [ 574.810922] ? trace_hardirqs_on_caller+0x3f4/0x560 [ 574.813890] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 574.816783] ? trace_hardirqs_on_caller+0x3f4/0x560 [ 574.819693] SyS_recvmsg+0x2d/0x50 [ 574.822829] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 574.825697] RIP: 0033:0x7f7fbd77e3c0 [ 574.828366] RSP: 002b:00007f7fba39ed50 EFLAGS: 00000293 ORIG_RAX: 000000000000002f [ 574.833588] RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007f7fbd77e3c0 [ 574.838882] RDX: 0000000000000000 RSI: 00007f7fba39edb0 RDI: 0000000000000008 [ 574.844377] RBP: 0000000000000046 R08: 0000000000000000 R09: 000000a0ff7159c1 [ 574.849937] R10: 00143f7b62d9620b R11: 0000000000000293 R12: 0000000000000000 [ 574.855391] R13: 0000000004000000 R14: 00007f7fa0000b10 R15: 0000000000000001 [ 574.860146] [ 574.862738] Allocated by task 2291: [ 574.865528] save_stack_trace+0x16/0x20 [ 574.868370] save_stack+0x46/0xd0 [ 574.871096] kasan_kmalloc+0xad/0xe0 [ 574.873838] __kmalloc+0x115/0x2d0 [ 574.876524] __vring_new_virtqueue+0x6a/0x790 [ 574.879432] vring_create_virtqueue+0x203/0x380 [ 574.882367] setup_vq+0x159/0x660 [ 574.885115] vp_setup_vq+0xbe/0x390 [ 574.887802] vp_find_vqs_msix+0x568/0xb90 [ 574.890494] vp_find_vqs+0x93/0x460 [ 574.893175] vp_modern_find_vqs+0x44/0x170 [ 574.895932] init_vqs+0x8eb/0x1150 [virtio_net] [ 574.898778] virtnet_restore_up+0x4c/0x5c0 [virtio_net] [ 574.901889] virtnet_xdp+0x820/0xd00 [virtio_net] [ 574.904858] dev_change_xdp_fd+0x1bb/0x340 [ 574.907708] do_setlink+0x23fb/0x2c00 [ 574.910491] rtnl_setlink+0x280/0x340 [ 574.913448] rtnetlink_rcv_msg+0x288/0x680 [ 574.916348] netlink_rcv_skb+0x340/0x470 [ 574.919165] rtnetlink_rcv+0x2a/0x40 [ 574.922027] netlink_unicast+0x58d/0x860 [ 574.924897] netlink_sendmsg+0x8d2/0xca0 [ 574.927815] sock_sendmsg+0xca/0x110 [ 574.930708] SYSC_sendto+0x20d/0x340 [ 574.933562] SyS_sendto+0x40/0x50 [ 574.936380] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 574.939322] [ 574.941724] Freed by task 2291: [ 574.944389] save_stack_trace+0x16/0x20 [ 574.947107] save_stack+0x46/0xd0 [ 574.949893] kasan_slab_free+0x72/0xc0 [ 574.952526] kfree+0xe6/0x2c0 [ 574.955082] vring_del_virtqueue+0xef/0x220 [ 574.957773] del_vq+0x126/0x270 [ 574.960283] vp_del_vqs+0x1f5/0xa30 [ 574.962743] virtnet_del_vqs+0xb7/0xf0 [virtio_net] [ 574.965930] virtnet_xdp+0x7b8/0xd00 [virtio_net] [ 574.968762] dev_change_xdp_fd+0x309/0x340 [ 574.971487] do_setlink+0x23fb/0x2c00 [ 574.974041] rtnl_setlink+0x280/0x340 [ 574.976727] rtnetlink_rcv_msg+0x288/0x680 [ 574.979366] netlink_rcv_skb+0x340/0x470 [ 574.981949] rtnetlink_rcv+0x2a/0x40 [ 574.984462] netlink_unicast+0x58d/0x860 [ 574.987151] netlink_sendmsg+0x8d2/0xca0 [ 574.989736] sock_sendmsg+0xca/0x110 [ 574.992351] SYSC_sendto+0x20d/0x340 [ 574.995262] SyS_sendto+0x40/0x50 [ 574.998959] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 575.001625] [ 575.003976] The buggy address belongs to the object at ffff88005d220000 [ 575.003976] which belongs to the cache kmalloc-8192 of size 8192 [ 575.010183] The buggy address is located 32 bytes inside of [ 575.010183] 8192-byte region [ffff88005d220000, ffff88005d222000) [ 575.016265] The buggy address belongs to the page: [ 575.019125] page:ffffea0001748800 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 [ 575.025320] flags: 0x100000000008100(slab|head) [ 575.028167] raw: 0100000000008100 0000000000000000 0000000000000000 0000000100030003 [ 575.031632] raw: dead000000000100 dead000000000200 ffff88006c802280 0000000000000000 [ 575.035447] page dumped because: kasan: bad access detected [ 575.039170] [ 575.041893] Memory state around the buggy address: [ 575.045408] ffff88005d21ff00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 575.051399] ffff88005d21ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 575.057558] >ffff88005d220000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 575.063760] ^ [ 575.069310] ffff88005d220080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 575.075359] ffff88005d220100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 575.081461] ================================================================== [ 575.086914] Disabling lock debugging due to kernel taint [ 575.090717] virtio_net virtio1: output.0:id 31 is not a head! [ 575.096336] net enp0s4: Unexpected TXQ (0) queue failure: -5 [ 575.102000] net enp0s4: Unexpected TXQ (0) queue failure: -5 [ 575.107383] net enp0s4: Unexpected TXQ (0) queue failure: -5 [ 575.112785] net enp0s4: Unexpected TXQ (0) queue failure: -5 [ 575.118228] net enp0s4: Unexpected TXQ (0) queue failure: -5 (gdb) l *(free_old_xmit_skbs+0x29b) 0x20db is in free_old_xmit_skbs (drivers/net/virtio_net.c:1051). 1046 1047 static void free_old_xmit_skbs(struct send_queue *sq) 1048 { 1049 struct sk_buff *skb; 1050 unsigned int len; 1051 struct virtnet_info *vi = sq->vq->vdev->priv; 1052 struct virtnet_stats *stats = this_cpu_ptr(vi->stats); 1053 unsigned int packets = 0; 1054 unsigned int bytes = 0; 1055 Best regards, Jean-Philippe
On Fri, Jun 23, 2017 at 1:43 AM, Jason Wang <jasowang@redhat.com> wrote: > > > On 2017年06月23日 02:53, Michael S. Tsirkin wrote: >> >> On Thu, Jun 22, 2017 at 08:15:58AM +0200, jean-philippe menil wrote: >>> >>> Hi Michael, >>> >>> from what i see, the race appear when we hit virtnet_reset in >>> virtnet_xdp_set. >>> virtnet_reset >>> _remove_vq_common >>> virtnet_del_vqs >>> virtnet_free_queues >>> kfree(vi->sq) >>> when the xdp program (with two instances of the program to trigger it >>> faster) >>> is added or removed. >>> >>> It's easily repeatable, with 2 cpus and 4 queues on the qemu command >>> line, >>> running the xdp_ttl tool from Jesper. >>> >>> For now, i'm able to continue my qualification, testing if xdp_qp is not >>> null, >>> but do not seem to be a sustainable trick. >>> if (xdp_qp && vi->xdp_queues_pairs != xdp_qp) >>> >>> Maybe it will be more clear to you with theses informations. >>> >>> Best regards. >>> >>> Jean-Philippe >> >> >> I'm pretty clear about the issue here, I was trying to figure out a fix. >> Jason, any thoughts? >> >> > > Hi Jean: > > Does the following fix this issue? (I can't reproduce it locally through > xdp_ttl) It is tricky here. From my understanding of the code base, the tx_lock is not sufficient here, because in virtnet_del_vqs() all vqs are deleted and one vp maps to one txq. I am afraid you have to add a spinlock somewhere to serialized free_old_xmit_skbs() vs. vring_del_virtqueue(). As you can see they are in different layers, so it is hard to figure out where to add it... Also, make sure we don't sleep inside the spinlock, I see a synchronize_net().
On 2017年06月24日 06:32, Cong Wang wrote: > On Fri, Jun 23, 2017 at 1:43 AM, Jason Wang <jasowang@redhat.com> wrote: >> >> On 2017年06月23日 02:53, Michael S. Tsirkin wrote: >>> On Thu, Jun 22, 2017 at 08:15:58AM +0200, jean-philippe menil wrote: >>>> Hi Michael, >>>> >>>> from what i see, the race appear when we hit virtnet_reset in >>>> virtnet_xdp_set. >>>> virtnet_reset >>>> _remove_vq_common >>>> virtnet_del_vqs >>>> virtnet_free_queues >>>> kfree(vi->sq) >>>> when the xdp program (with two instances of the program to trigger it >>>> faster) >>>> is added or removed. >>>> >>>> It's easily repeatable, with 2 cpus and 4 queues on the qemu command >>>> line, >>>> running the xdp_ttl tool from Jesper. >>>> >>>> For now, i'm able to continue my qualification, testing if xdp_qp is not >>>> null, >>>> but do not seem to be a sustainable trick. >>>> if (xdp_qp && vi->xdp_queues_pairs != xdp_qp) >>>> >>>> Maybe it will be more clear to you with theses informations. >>>> >>>> Best regards. >>>> >>>> Jean-Philippe >>> >>> I'm pretty clear about the issue here, I was trying to figure out a fix. >>> Jason, any thoughts? >>> >>> >> Hi Jean: >> >> Does the following fix this issue? (I can't reproduce it locally through >> xdp_ttl) > It is tricky here. > > From my understanding of the code base, the tx_lock is not sufficient > here, because in virtnet_del_vqs() all vqs are deleted and one vp > maps to one txq. > > I am afraid you have to add a spinlock somewhere to serialized > free_old_xmit_skbs() vs. vring_del_virtqueue(). As you can see > they are in different layers, so it is hard to figure out where to add > it... > > Also, make sure we don't sleep inside the spinlock, I see a > synchronize_net(). Looks like I miss something. I thought free_old_xmit_skbs() were serialized in this case since we disable all tx queues after netif_tx_unlock_bh()? Jean: I thought this could be easily reproduced by e.g produce some traffic and in the same time try to attach an xdp program. But looks not. How do you trigger this? What's your qemu command line for this? Thanks
On 06/26/2017 04:50 AM, Jason Wang wrote: > > > On 2017年06月24日 06:32, Cong Wang wrote: >> On Fri, Jun 23, 2017 at 1:43 AM, Jason Wang <jasowang@redhat.com> wrote: >>> >>> On 2017年06月23日 02:53, Michael S. Tsirkin wrote: >>>> On Thu, Jun 22, 2017 at 08:15:58AM +0200, jean-philippe menil wrote: >>>>> Hi Michael, >>>>> >>>>> from what i see, the race appear when we hit virtnet_reset in >>>>> virtnet_xdp_set. >>>>> virtnet_reset >>>>> _remove_vq_common >>>>> virtnet_del_vqs >>>>> virtnet_free_queues >>>>> kfree(vi->sq) >>>>> when the xdp program (with two instances of the program to trigger it >>>>> faster) >>>>> is added or removed. >>>>> >>>>> It's easily repeatable, with 2 cpus and 4 queues on the qemu command >>>>> line, >>>>> running the xdp_ttl tool from Jesper. >>>>> >>>>> For now, i'm able to continue my qualification, testing if xdp_qp >>>>> is not >>>>> null, >>>>> but do not seem to be a sustainable trick. >>>>> if (xdp_qp && vi->xdp_queues_pairs != xdp_qp) >>>>> >>>>> Maybe it will be more clear to you with theses informations. >>>>> >>>>> Best regards. >>>>> >>>>> Jean-Philippe >>>> >>>> I'm pretty clear about the issue here, I was trying to figure out a >>>> fix. >>>> Jason, any thoughts? >>>> >>>> >>> Hi Jean: >>> >>> Does the following fix this issue? (I can't reproduce it locally through >>> xdp_ttl) >> It is tricky here. >> >> From my understanding of the code base, the tx_lock is not sufficient >> here, because in virtnet_del_vqs() all vqs are deleted and one vp >> maps to one txq. >> >> I am afraid you have to add a spinlock somewhere to serialized >> free_old_xmit_skbs() vs. vring_del_virtqueue(). As you can see >> they are in different layers, so it is hard to figure out where to add >> it... >> >> Also, make sure we don't sleep inside the spinlock, I see a >> synchronize_net(). > > Looks like I miss something. I thought free_old_xmit_skbs() were > serialized in this case since we disable all tx queues after > netif_tx_unlock_bh()? > > Jean: > > I thought this could be easily reproduced by e.g produce some traffic > and in the same time try to attach an xdp program. But looks not. How do > you trigger this? What's your qemu command line for this? > > Thanks Hi Jason, this is how i trigger the bug: - on the guest, tcpdump on on the interface - on the guest, run iperf against the host - on the guest, cat /sys/kernel/debug/tracing/trace_pipe - on the guest, run one or two instances of xdp_ttl compiled with DEBUG uncommented, that i start stop, until i trigger the bug. qemu command line is as follow: qemu-system-x86_64 -name ubuntu --enable-kvm -machine pc,accel=kvm -smp 2 -drive file=/dev/LocalDisk/ubuntu,if=virtio,format=raw -m 2048 -rtc base=localtime,clock=host -usbdevice tablet --balloon virtio -netdev tap,id=ubuntu-0,ifname=ubuntu-0,script=/home/jenfi/WORK/jp/qemu/if-up,downscript=/home/jenfi/WORK/jp/qemu/if-down,vhost=on,queues=4 -device virtio-net-pci,netdev=ubuntu-0,mac=de:ad:be:ef:01:03,mq=on,guest_tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off,vectors=2 -vnc 127.0.0.1:3 -nographic -serial file:/home/jenfi/WORK/jp/qemu/ubuntu.out -monitor unix:/home/jenfi/WORK/jp/qemu/ubuntu.sock,server,nowait Notice, the smp 2, queues to 4 and vectors to 2. Seem that if fogot to mention that in the beginning of this thread, sorry for that. Best regards. Jean-Philippe
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1f8c15c..3e65c3f 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1801,7 +1801,9 @@ static void virtnet_freeze_down(struct virtio_device *vdev) /* Make sure no work handler is accessing the device */ flush_work(&vi->config_work); + netif_tx_lock_bh(vi->dev); netif_device_detach(vi->dev); + netif_tx_unlock_bh(vi->dev); cancel_delayed_work_sync(&vi->refill);